Valve mechanism for steam-engines



E. E. BASHAW AND N. M. NELSON. VALVE MECHANISM FOR STEAM ENGINES;

APPLICAUON'FILED 00111, 1919. V v 1,363,554., Patented Dec. 28, 1920.

2 SHEETS-SHEET 1- E. E. BASHAW AND N. M. NELSON.

-VALVE MECHANISM FOR STEAM ENGINES.

APPLICATION FILED OCT. 11, 1919.

1,868,554, Patented Dec. 28,1920.

2 SHEETSSHEET 2.

mvrrnn EDWIN E. BASI-IAW, 0F DAVENFOR'i, IONA AND NELS M. NELSON, OF ROCHESTER, MINNESOTA.

VALVE MECHANISM FOR STEAM-ENGINES.

Specification of Letters Patent.

Patented Dec. 28, 192d.

Application filed ()ctober 11, 1919. Serial No. 330,077.

To all whom it may concern:

Be it known that we, EDWIN E. BASHAW and Nine M. NELSON, citizens of the United States residing, respectively, at Davenport, county of Scott, State of-Iowa, and Rochester, county of Olmstead, State of Minnesota, have invented certain new and useful Improvements in Valve Mechanisms for Steamingines, of which the following is a specification.

Our invention relates to improvements in valve mechanisms for steam engines, and

. more particularly appertains. to means for actuating the valves without an eccentric.

An object of our invention is the produc tion of'such a device in which the piston itself actuates the valves.

Another object is to provide means for simultaneously actuating the inlet and exhaust valves.

A further object is to provide inlet and exhaust valves at each end of the cylinder and means connecting them all, so that they may all be actuated simultaneously.

A still further object is to provide means for regulating the time of closing the inlet valve, irrespective of the exhaust valve.

A still further object is to provide means for adjusting the timing mechanism.

Further objects and advantages will be apparent upon a perusal of the specification in connection with the accompanying drawings, in which:

igure 1 is a longitudinal vertical section;

Fig. 2 is an enlarged detail view of the admission valve timing mechanism in the path of travel of the reciprocating crosshead;

Fig. 3 is a fragmentary view of the upper portion of the admission valve mechanism;

Fig. 4 is an enlarged detail view of the gearing of the admission valve timing mechanism.

The cylinder 1 is provided with the customary reciprocating piston 2 connected with the piston rods 3'3 which terminate in the customary sliding cross head 4.

In one end of the cylinder, the common port 5 is provided through which passes the live and exhausted steam, or other expanding fluid. The port 5 opens into the valve casing 6, in which the exhaust valve 7 1s adjustably affixed to the slidable rod 8, which is adapted to extend through the port 5 into the expansion chamber in the cylinder 1, in passing to be struck by the piston 2. The other end of the slidable rod 8 has pivotally connected to it at 9 the bell-crank lever 10 pivoted at 11 to the rigid bar 12.

The other end of the bell-crank lever 10 has pivotally connected to it a link 13, which is in turn pivotally connected at 14 to the compound bell-crank lever 15 which is fulcrumed at 16 on the rigid support 17 connected to the valve-casing 6. One arm 18 of the compound-bell-crank lever 15 has a link 19 pivotally connected thereto, which link 19 is pivotedat itstermination to the vertically reciprocating cross-head 20.

Cross-head 20 is preferably provided with a slot 21 in the center thereof, in which a pair of spaced tripping-levers 2222 are pivotally supported and which are provided with shoulders 23 23, adapted to normally engage the under surface of the enlarged portion 24 of the vertically slidable inlet valve rod 25.

The tripping levers 2222 are normally held in their engaged position by means of a constricted s ring 26. A horizontal bracing member 2 is provided, between which and the shoulder 28 of the rod 25 a helical spring 29 is adapted to press. The rod 25 is adjustably mounted in said bracing member 27 and inlet valve 30 is adapted to close upon the seat 31 in the valve casing 6.

In the mechanism thus far described, it will be apparent that presuming the exhaust valve 7 to be opened and the inlet valve 30 closed, the piston 2 as it nears the end of its stroke will strike the end of the. slide rod 8 and immediately close the exhaust valve 7 by causing it to impinge against the valve seat 32. Longitudinal movement of the rod 8 will cause actuation of the bell crank lever 10, link 18 and compound bell crank lever 15 through which an upward thrust is given to the link 19, and the cross-head 20 carrying the trip-levers 22, which in turn support the valve rod 25, will actuate the rod 25 vertically so that the valve 30 will be opened.

The mechanism for the other end of the cylinder is precisely the same as that which has just been described, and it is not believed necessary to make further explanations other than to state that an arm 33 of the compound bell crank lever 15 is pivotally connected with the connecting rod 34:, in turn pivotally connected with the arm 33' of the compound bell crank lever 15. 7

It will thus be seen that the immediate effect of the actuation of the rod 8 to the left will'be to close the exhaust valve 7 and open the valve 30, thus giving the piston 2 the impelling power necessary to force it to the other end of the cylinder.

Simultaneously with this, however, the connecting rod 34 has been actuated and the immediate effect will be to drop the intake valve and to open exhaust valve 7 so that there will be no conflicting expansion on the opposite side of the piston 2 thereby it is controlled by the passage of the steam from the inlet valve 30. We preferably provide a common main 35 for the live steam which branches at 36 and 37 so as to introduce live steam at both ends of the cylinder Any preferred form of exhaust mains or conduits may be utilized.

In the event that the engine is at a standstill from stalling or otherwise, mechanism is provided. to permit of the reversal of it at'will. 38 turning about the usual quadrant 39 and having pivotally connected to one end the link 40 which in turn is pivotally connected to the lever 41,pivoted at 42, and has an opening 43 in one end, through which the connecting rod 34 passes.

A customary bell-crank lever 44 is mounted on the handle of the lever 38, and through a system of bell-crank levers and links 45, 46, 47 and 48 respectively a vertical movement can be given to the sliding pin 49, one end of which is adapted to enter recesses on the connecting rod 34.

It will be apparent that squeezing the grip 44 will result in pulling down upon the pin 49 into engagement with a recess 50 on the connecting rod 34, and that upon the oscillation of the lever 38 about its pivot, longitudinal reciprocation of the connectingrod 34 is accomplished with the result that the valves, connected as they are by a series of levers and links to act simultaneously, will reverse their positions as desired;

In an engine of this type, it is desirable to prematurely close the inlet valves so as to regulate the speed. This is accomplished preferably in the following manner:

Two parallel bars .51 and 52 having right and l'eft'hand screw-threads thereon are connected through a train of gears 53 to turn simultaneously in the same direction. The upper rod 52 is capable of longitudinal reciprocation. Helical springs 54 and 55 are preferably provided for normally holding the rod 52 in one position.

On one end 'of the rod 51 a threaded collar 56, which has the upstanding arm 57 attached thereto, is screwed, which forms a fulcrum for the bell-crank lever 58. This This mechanism comprises a lever v bell crank lever 58 is connected, by a link 59 to the tappet 60, on the threaded collar 56.

Onetarm of the bell crank lever 58 has a slot 61 which is engaged by a lug 62 on the screwthreaded sleeve 63, screwed on one end of the rod 52.

A similar threaded collar 64 is provided on the other end of rod 51 and carries tappet 65 which is connected by link 66 to the lever 67 fulcrumed on-the upstanding support 68 fastened to the collar 64.

The tappets and face in opposite directions, but will give the rod 52 a smart pull longitudinally to the left when they are struck by the cross-head 4.

The rod 52 is connected through a swivel 69 to a rod 70, which is pivotally connected with the lever 71, pivot-ed on the same fulcrum 16, as lever 15, which hasat its upper end a pivotal engagement at 72 with the 35 link 72, pivoted to bellcrank lever 73. The lever 71 also pivotally engages the/connecting rod 74, which in turn engages the bellcrank lever 75.

The bell-crank levers 73 and 75 are substantially the same, and comprise a T- shaped lever having a counter-balance 7.6 on one end and the other has pivotal connection with the sliding releasing crossheads 77 and 77 respectively. These releasing cross-heads are made with an opening in the center, preferably in the form of a ring which is adapted to be forced down into engagement withthe trip levers 22, 22, for forcing their upper edges together, and thus to cause them to loosen their hold on the valve rod 25, so that the rod will fall and close by gravity, and also because of the steam pressure behind it, as well as by the expansive force of spring 29.

It is the function of the tappets 65 and 60 to govern this fall of the intake valve rods.

As far as described it will be apparent that, presuming mechanism to be in position ShOWH in g. 2 the cross-head 4 will hold the tappet 60 up, thus forcing the rod 52 to the left, and actuating the connecting rod 74 to the right, thus forcing the crossheads 77 and 77 up from the raised trip levers 2222, thus permitting th expansion 115 chamber to fill with steam.

hen cr0sshead 4 has proceeded farther. the tappet 60 drops off. and the springs 54 and return the rod'52- to the rightJthus droppingboth cross-heads77 and 77 upon 120 whichever trip-fingers 2222 were raised,

due to the opening of the admission valve.

This at once' cuts off the steam and the pisten 2 rides the rest of the way without additional impetus. lVhen the tappet 65 is reached by cross-head 4, the rod 52 is forced to'the left and the cross-heads 77 and 77 raised, so that when the valve rod 8 is struck the exhaust valve 7 is closed, intake 30 is opened, exhaust valve 7 is opened and the cross-head 20 drops down and engages the enlarged end 24- of the valve rod 25, preparatory to raising the valve 30, when necessary.

It is obvious that a necessity for changing the timing of the valves exists depending upon the pressure in the boiler, or the load on the engine, among other things, and it is therefore necessary that means be provided for varying the time at which the valves 30 and 30 may be closed.

This may be done either by rotation of one of the bars 51 or 52 when the train of gears will actuate them simultaneously, and owing to the right and left hand screw threads the bars 51 and 52, the collars 64: and 56 will be drawn closer together or farther apart according to the direction that the rods are turned.

Another means for providing for the variation of the timing of these valves, would be to have the rod 51 continued out a little distance, and. have a gear wheel 78 mounted on the end thereof in engagement with a rack bar '79, which is capable of vertical reciprocation, and is actuated by a collar 80' on. an ordinary governor 81.

It will be seen as the speed increases, the rack bar will be raised and bars 51 and 52 will be rotated and the tappets will be forced farther apart with a corresponding quickening of the shutting off of the live steam.

It is obvious that by means of a rotatable shaft 82 connected with a universal joint 83 to the rod 51, that our invention could be applied to locomotive cabs and would be capable of easy adjustment by the engineer thercoi.

It is obvious that many slight changes might be made in our construction without departing from the spirit oi the invention, hence we do not wish to be limited to the structure set forth, but

We claim:

1. In an engine having inlet and exhaust ports, valves tor said ports, and valve-rods connected to said valves, a reciprocating crosshead, tripping fingers pivotally mounted on said cross-head and normally engaging one oi said valve-rods, means for actuattheir hold upon the valve rod is released and the valve connected to said engaged valve rod may be closed independently of the other valves, and means for actuating said releasing cross-head at variable intervals.

2. In an en ine having inlet and exhaust ports, valves for said ports, and valve-rods connected to said valves, a reciprocating cross-head, tripping fingers pivotally mounted on said cross-head and normally engaging one of said valve-rods, means for actuating the said valves simultaneously including a lever for reciprocating said cross-head, a releasin cross-head adapted to move said tripping-fingers about their pivots so that their hold upon the valve rod is released and the valve connected to said engaged valve rod may be closed independently of the other valves, means for actuating said releasing cross-head at variable intervals, said means comprising spaced parallel bars, tappets pivotally mounted on one of said bars and connected by levers to the other bar, said tappets located in the path of travel of part of one moving element of the engine and adapted when struck to give the last-mentioned bar an impulse, and a train of levers connected between the last-mentioned bar and said releasing cross-head, whereby the impulse is transmitted to the releasing crosshead.

3. In an engine, a valve actuated by tripping mechanism, means for releasing the tripping mechanism including a pair of spaced parallel bars, tappets pivotally mounted on one bar and connected by levers to sleeves on the other bar, means for varying the distance between the tappets, each of said tappet-s being in the path of travel of a moving element of the engine, and adapted when struck to give the last-mentioned bar an impulse, means for returning said lastmentioned bar to its normal position after each impulse, and a train of levers connected between said last-mentioned bar and the trip releasing element.

4. In an engine having inlet and exhaust ports, valve rods and valves for said ports, valve-gear including a connecting rod engaging with said valve-rods for actuating all of said valves simultaneously, a manually controlled lever, a manually-controlled sliding pin mounted on the lever in position to engage said connecting rod, whereby the position of the valves may be reversed upon the actuation of the lever and sliding pin.

In testimony whereof we affix our signatures.

NELS M. NELSON. EDWIN E. BASHAW. 

